I bought a Philips 47PFL6907H. It worked perfectly fine, I used the TV guide (both cable and internet), which worked perfectly. Agfter connecting to the internet, the TV asked to be updated. After the update, I can now no longer change the channel while on the TV guide by pressing "OK", whether on the internet IP-EPG or the broadcaster-EPG.

I downloaded the latest firmware update from philips on a USB stick and installed it ; this did not solve the problem.